Ok ok, I'll make a better suggestion. I took an adjustable sling that was slightly small, kinda like a gym bag, as long as it has square ends. And so you just loop duct tape through one end of the sling and attach that to the beginning of the stock (use a few layers for durability), you just can't put your stock on the first setting. Then loop the free end of the sling through your vest or through a D-ring on the shoulder (only if it has one) of through a MOLLE loop, it'll be a tight fit, and duct tape it over the attached end. It worked out good for me for a while, just needs a little care and repair after a while.
